With 60 million tonnes per year, grape is the first fruit production in the world. Most of the grape is used for wine production. Some 60% of the world's wine is produced in the EC, especially in France, Italy and Spain. Wine production generates a large amount of solid waste (around 20-30% of the processed material; estimated at between 5 and 9 million tonnes annually worldwide and 4.5 million tonnes in the EC) (Awarenet, 2004; Schieber et al., 2001) and wastewater (1 litre for 1 litre of wine produced).
The majority of the solid wastes are produced during the first steps of the processing of the grapes. Grapes are harvested and crushed, resulting in mash and stems (2-8% of processed material). The mash is then pressed and separated into juice and pomace (10-20%). Stems and pomace are the principal by-products of wine production and are the source of valuable components (ethanol (see Section 16.5.4), tartrate, citric acid (see Section 16.5.5), hydrocolloids (see Section 16.4), dietary fibres (see Section 16.3.1)) (Schieber et al., 2001). High-value antioxidants can be extracted from stems - such as resveratrol used in nutraceuticals, cosmetics or biopharmaceuti-cals. Pomace also contains other antioxidants (procyanidins, polyphenol extracts) and pigments (anthocyanin) (Tomas-Barberan et al., 2004) and can be used for production of grape seed oil.
In the main wine-producing countries, solid wastes have to be treated in distilleries, which recover spirits by distillation and extraction of grape seed oil and incinerate the final waste. In other countries solid wastes can be used as a fertiliser.
Was this article helpful?